1. Field of the Invention
This invention relates to an onboard connector (in other words, a circuit board direct-mounting connector) having electrically-conductive metal terminals (hereinafter referred to merely as “terminals”) received in a connector housing, these terminals being mounted on an electric circuit board (hereinafter referred to merely as “circuit board”).
2. Description of the Related Art
In a vehicle such as an automobile, electrical equipment parts, mounted on the vehicle, are required to have a compact design in order to increase a space within a car room. Therefore, it is also required to reduce an area occupied by a circuit board (mounted as an electrical equipment part on the vehicle) in the vehicle. As one method of reducing the area of the board, it has now become necessary to use a SMD type (that is, a surface mounting type) onboard connector instead of a conventional DIP type (that is, a discrete type) onboard connector.
However, taking into consideration the connecting reliability of joined portions (that is, electrically-contacted portions) of terminals and respective lands of the circuit board against warp of the circuit board, it is rather difficult to use the SMD type onboard connector on the onboard circuit board which is required to have a high reliability under severe environments. And besides, in the case where this SMD type onboard connector is, for example, a multi-pole connector with a large number of terminals or a large-size connector having a large connector housing, it is more difficult to use the SMD type onboard connector on the onboard circuit board.
FIG. 11 shows one example of a structure of an electric part which has heretofore been proposed in order to enhance the connecting reliability of joined portions of terminals and respective lands (see JP-UM-A-5-85032 Publication). Description will now be made, assuming that the electric part, shown in FIG. 11, is an onboard connector. In this onboard connector 150, in order that soldier fillets, formed respectively at joined portions of a plurality of SMD type terminals 152 and respective lands on a circuit board 153, can be prevented from being broken by warp of the circuit board 153, a slit (not shown) is formed in a predetermined portion of each of the terminals 152 to divide this portion into a plurality of sections in a direction of a width of the terminal 152, and the divided sections are bent respectively in opposite directions to thereby enhance spring properties of the terminal 152. However, in the case where the onboard connector 150 is a multi-pole connector or a large-size connector, a larger number of terminals 152 are arranged long in a row in a juxtaposed manner, and therefore there is a strong possibility that this structure can not function well at all against warp of the circuit board 153 developing during reflowing. Namely, the larger the area, occupied by the onboard connector 150 on the circuit board 153, becomes, the more conspicuous the influence of the warp of the circuit board becomes.
FIG. 12 shows one conventional onboard connector in which the arrangement of a number of terminals is elaborated (see JP-A-2004-206924 Publication). In FIG. 12, constituent elements, similar to those of the structure of FIG. 11, are designated respectively by identical reference numerals for clarification purposes. In this onboard connector 150, the plurality of SMD type terminals 152 are divided into two groups in a direction of a width of a connector housing 151 to thereby achieve a narrow pitch design as shown in FIG. 12. However, the plurality of terminals 152 are arranged at a small pitch along the connector housing, and also the front row of terminals 152 and the rear row of terminals 152 are arranged in overlapping relation to each other, and therefore joined portions of the terminals and respective lands can not be easily examined. And besides, the onboard connector 150 of FIG. 12 has such a structure that inner housings 155 are received in respective front openings 154 in the connector housing 151, and therefore if the connector housing 151 is wrenched by a mating connector when fitting the mating connector to the onboard connector 150, an external force from the mating connector acts directly on the terminals 152, so that the connecting reliability of the joined portions of the terminals and the respective lands is lowered.